Viral nucleotide sequences

Abstract

Various genes of herpes virus of turkeys (HVT) Marek's disease virus (MDV) and infectious laryngotracheitis virus (ILTV) have been identified as non-essential regions (and candidates for insertion sites for foreign genes) and/or as antigen-encoding regions. The former include the HVT homologue of the HSV (herpes simplex virus) gC gene, the TK (thymidine kinase) region of MDV or ILTV, ORF3 of ILTV (as defined herein), the ribonucleotide reductase (large subunit) gene of ILTV, MDV or HVT and the ribonucleotide reductase (small subunit) gene of MDV. The antigen-encoding regions include the HVT homologues of the HSV gB, gC and gH genes, the ILTV homologue of HSV gB, ORF2 of ILTV, and the HVT homologue of the HSV-1 immediate early genes IE-175 and IE-68. Manipulation of these genes allows vaccines to be prepared comprising attenuated virus or virus carrying heterologous antigen-encoding sequences.

What is claimed is:  
     
       1. A recombinant ILTV synthetically modified by a mutation in an ILTV gene such that the recombinant ILTV is attenuated as a result of said mutation. 
     
     
       2. The ILTV according to  claim 1 , wherein the mutation is in the TK, ORF3 or ribonucleotide reductase, large subunit, gene. 
     
     
       3. The ILTV according to  claim 1 , synthetically modified by the presence, in a non-essential region of the ILTV genome, of DNA not naturally occurring in ILTV.